Subtree.java


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import java.lang.*;
import java.util.*;
import node.*;

class Subtree {
	public static boolean isSubtree(TreeNode root, TreeNode subRoot) {
		if (root == null && subRoot == null)
			return true;
		else if (root == null || subRoot == null)
		 	return false;
		else if (root.val == subRoot.val)
			return isSubtree(root.left, subRoot.left)
				&& isSubtree(root.right, subRoot.right);
		return isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
	}

	public static void main(String[] args) {
		TreeNode leftLeaf = new TreeNode(1);
		TreeNode middleLeaf = new TreeNode(2);
		TreeNode leftParent = new TreeNode(4, leftLeaf, middleLeaf);
		TreeNode rightLeaf = new TreeNode(5);
		TreeNode root = new TreeNode(3, leftParent, rightLeaf);
		TreeNode subLeft = new TreeNode(1);
		TreeNode subRight = new TreeNode(2);
		TreeNode subRoot = new TreeNode(4, subLeft, subRight);
		System.out.println(isSubtree(root, subRoot));
	}
}